A proxy server, or forward proxy server, is typically a server or application that can act as an intermediary for a client computing system that is seeking a resource from another server. One common type of proxy server is a web proxy that facilitates accessing content from the Internet. Generally, the client computing system is a computing system in an internal network. The client computing system can generate a request that identifies a target server for accessing a service or resource. This request is provided to the proxy server, which then forwards the request to the target server via the Internet. There are a number of types of forward proxy servers in existence today. For example, an open proxy is a type of forward proxy server.
In addition to forward proxy servers, there exist reverse proxy servers, or surrogate proxy servers. A reverse proxy server receives requests from a computing system in an external network (e.g., the Internet) and forwards them to a server in an internal network for processing. In many cases, the computer system generating the request may not be aware of the existence of the server of the internal network.